Imaging Techniques in Nuclear Cardiology for the Assessment of Myocardial Viability

Abstract

The assessment of myocardial viability has become an important aspect of the diagnostic and prognostic work-up of patients with ischemic cardiomyopathy. Although revascularization may be considered in patients with sufficient viable myocardium, patients with predominantly scar tissue should be treated medically. Patients with left ventricular dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischemia but at the same time benefit most from revascularization. It is important to identify viable myocardium in these patients, and radionuclide myocardial scintigraphy is an excellent tool for this. Single-photon emission computed tomography perfusion scintigraphy (SPECT), whether using (201)thallium, (99m)Tc-sestamibi, or (99m)Tc-tetrofosmin, in stress and/or rest protocols, has consistently been shown to be an effective modality for identifying myocardial viability and guiding appropriate management. Metabolic and perfusion imaging with positron emission tomography (PET) radiotracers frequently adds additional information and is a powerful tool for predicting which patients will have an improved outcome from revascularization. New techniques in the nuclear cardiology field, like attenuation corrected SPECT, dual isotope simultaneous acquisition (DISA) SPECT and gated FDG PET are promising and will further improve the detection of myocardial viability. Also the combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and non-invasive coronary angiography to myocardial perfusion imaging and quantification. Evaluation of the clinical role of these creative new possibilities warrants investigation.

A novel gallium bisaminothiolate complex as a myocardial perfusion imaging agent

“…It was purified as its HCl salt by bubbling anhydrous HCl gas through its solution in anhydrous ether (6.39 g, 78%). 1 …”

“…The compound was then extracted with 10% MeOH in DCM to afford pure free base 8. 1 Crystals for X-ray structure determination were obtained through recrystallization from methylene chloride/hexane.…”

“…Myocardial perfusion has been traditionally evaluated with planar imaging or single photon emission computed tomography (SPECT), in conjunction with radiopharmaceuticals such as 201 Tl, [ 99m Tc]sestamibi or [ 99m Tc]tetrofosmin [1,2]. Currently, these types of myocardial perfusion imaging studies are part of normal patient workup and are performed on a routine basis.…”

Diagnostic accuracy of myocardial perfusion imaging with single photon emission computed tomography and positron emission tomography: a comparison with coronary angiography

“…Compared to SPECT, PET offers several potential advantages, such as: a higher spatial resolution, lower effective dose due to greater counting efficiency, and higher temporal resolution, allowing fast dynamic imaging of tracer kinetics and thus absolute quantification of myocardial perfusion [2][3][4]. These advantage have presumably influenced the results of consecutive studies, confirming the higher sensitivity and specificity of PET [1,[5][6][7][8].…”

Coronary artery calcium screening: sufficient evidence for accurate risk assessment?

“…Consequently, cardiac risk assessment is mostly warranted in asymptomatic patients, particularly in those at intermediate risk. It has been suggested that traditional risk assessment may be refined with the selective use of newer imaging methods, such as coronary artery calcium scoring and noninvasive angiography with computed tomography (CT) techniques [1][2][3][4][5][6]. These technologies, which allow quantification of atherosclerotic burden, can predict risk of cardiac events and might provide an approach to more widespread coronary atherosclerosis screening [7].…”